#include<stdlib.h>
#include<stdio.h>

void merge(int arr[], int l, int m, int r);
void mergeSort(int arr[], int l, int r)
{
   if (l < r)
   {
      // Same as (l+r)/2 but avoids
      // overflow for large l & h
      int m = l+(r-l)/2;
      mergeSort(arr, l, m);
      mergeSort(arr, m+1, r);
      merge(arr, l, m, r);
   }
}



void merge(int arr[], int l, int m, int r)
{
    int i, j, k;
    int n1 = m - l + 1;
    int n2 =  r - m;


    int L[100], R[100];
    for (i = 0; i < n1; i++)
	L[i] = arr[l + i];
    for (j = 0; j < n2; j++)
	R[j] = arr[m + 1+ j];


    i = 0;
    j = 0;
    k = l;
    while (i < n1 && j < n2)
    {
	if (L[i] <= R[j])
	{
	    arr[k] = L[i];
	    i++;
	}
	else
	{
	    arr[k] = R[j];
	    j++;
	}
	k++;
    }

    while (i < n1)
    {
	arr[k] = L[i];
	i++;
	k++;
    }
    while (j < n2)
    {
	arr[k] = R[j];
	j++;
	k++;
    }
}


void printArray(int A[], int size)
{
    int i;
    for (i=0; i < size; i++)
	printf("%d ", A[i]);
    printf("\n");
}


int main()
{
    int arr[] = {12, 11, 13, 5, 6, 7};
    int arr_size = sizeof(arr)/sizeof(arr[0]);
    printf("Given array is \n");
    printArray(arr, arr_size);
    mergeSort(arr, 0, arr_size - 1);
    printf("\nSorted array is \n");
    printArray(arr, arr_size);
    return 0;
}